Guardian of the Heart by M. L. Buchman

-a Night Stalkers CSAR romance novella- The most dangerous mission of all...CSAR. Combat Search and Rescue. Noreen Wallace cares about only two things: saving lives, and her family. Following in her big brother’s path, she flies into battle armed with a stretcher and a med kit. Xavier Jones only family is the Army. No point in believing anything more exists—until he saves the Guardian of the Heart.